Posted
by
samzenpuson Monday March 24, 2014 @03:17PM
from the where-should-I-put-this? dept.

Lasrick (2629253) writes "An underground fire and a separate plutonium leak at the Waste Isolation Pilot Plant (WIPP) has left the US with no repository for transuranic (TRU) waste--that is, radioactive elements heavier than uranium on the periodic chart, such as plutonium, americium, curium and neptunium. WIPP is a bedded salt formation in New Mexico, chosen because of its presumed long-term stability and self-sealing properties, and it currently holds, among other things, 4.9 metric tons of plutonium. Despite assurances from the DOE that the plant would soon reopen, New Mexico has cancelled WIPP's disposal permit indefinitely. Robert Alvarez, who has served as senior policy adviser to the Energy Department's secretary and as deputy assistant secretary for national security, explores what happened at WIPP, and what it means for defense nuclear waste storage."

[sigh]
Yet another contractor who seems to have been doing the minimum required to get paid. Fire suppression turned off, flammable materieals stored after repeated inspections required that they be removed. Outsource responsibility and this seems to be the result. Words cannot express how disappointed I am that "business" seems to be going on "as usual" even when managing something as hazardous as nuclear waste.

Turn it over to the Navy submarine command, they seem to be the only ones who give a damn about nuclear safety (the airforce certainly doesn't, between putting warheads on the wrong plane and the rampant cheating in the missile command that's pretty obvious).

It's not "wackos" that are preventing the waste being used, it is the cost. What people like you don't understand is just because on paper you can build some cool piece of technology to deal with it doesn't mean it makes commercial sense to do so. No-one has been able to demonstrate a working commercial scale reactor of this type yet, and the smaller research/prototype ones have all had major issues.

If you can find someone willing to invest tens of billions in building one of these things and getting regulatory approval/certification, and taking on the risk of some problem developing during its lifetime that costs a fortune to fix or writes it off... Well, go ahead and build one. Until them stop whining and blaming imaginary boogiemen for not getting your cool toy.

And yeah, putting it in the ground is fine as long as you do it carefully so it doesn't get into the water table etc. You need to be sure that won't happen for tens or even hundreds of thousands of years, so it isn't a trivial thing to find a suitable spot and dig it out. Just like your first idea it looks easy on paper but in practice is somewhat more complex than you thought.

Yeah, you have to be French to not screw it up. Americans would surely screw it up. We don't know anything about nuclear technology. Derp!

Back to reality... maybe we should consider the face value... the nuclear industry is opposing those steps, because they're invested in particular technologies and the new technologies would enrich different companies than the ones already entrenched. Ah, now we have a reasonable explanation! And surprise surprise, it is also the standard explanation that "everyone" alrea

It's more political. Funding waste disposal research means first admitting that there is a waste disposal problem. For example Synroc was nearly complete in 1987 but had trouble getting funding and approval to use real waste for large scale trials until relatively recently. It was not an expensive project but committing any funding at all was seen as an admission that nuclear waste was not stored in a perfect way.

Let's see the cost of developing a new technology to dispose of the waste, as you estimate, would be billions of dollars. How much is it costing to store this waste currently? Who is paying for that?

The cost of storing this waste now has to paid for by the government, and has to cost millions of dollars per year. How much it costs exactly I do not know. We are pretty certain this storage cost will only increase and the waste will continue to be waste until we find something else to do with it.

It's not "wackos" that are preventing the waste being used, it is the cost. What people like you don't understand is just because on paper you can build some cool piece of technology to deal with it doesn't mean it makes commercial sense to do so.... If you can find someone willing to invest tens of billions in building one of these things and getting regulatory approval/certification, and taking on the risk of some problem developing during its lifetime that costs a fortune to fix or writes it off... Well, go ahead and build one.

Wikipedia seems to agree with you somewhat about the economics; but I would have to ask if the economics of waste disposal are being factored into non-breeder reactors. I suspect it is not and for political "wacko" reasons.

OMFG SOMETHING MIGHT GO WRONG... even when we put it in someplace that if something does go wrong... its okay... like this particular incident.
If you call blowing plutonium dust through the ventilation system "okay"...I think most people would say that's stretching the definition of "okay", just a bit.
And then there's the whole "oops, contractor f@cked up...again" problem that never quite seems to go away.

Half-life is half-life; there isn't a process we can use to change that

OK, to begin, the following is simplified to skip some points of extreme nuisance, and to be suitable for non nuclear engineers (like me).

Radioactive decay isn't as simple as one might be forgiven for thinking given the simplistic concept "half-life". You might ideally start off with a pure form of a single isotope of a single element. In practice, you never do. Reactor fuel as it goes into the reactor is about 5% U235, 95% U238, with traces of other elements and isotopes. When it comes out of the reactor, it is a lesser percentage of U235, still a bunch of U238 left, plus a bunch of plutonium and a witch's brew of other isotopes of elements resulting from the nuclear "cooking" in the reactor involving neutron bombardment.

But for simplicity, let's take an imaginary bunch of U235 [csupomona.edu].

The U235 decays to Th231 in a decay process with a half-life of 704 million yearsThe Th231 decays to Pa231 in a decay process with a half-life of 25.5 hoursThe Pa231 decays to Ac227 in a decay process with a half-life of 32,500 yearsThe Ac227 decays to 98.6% Th227 and 1.4% Fr223 in a decay process with a half-life of 21.6 yearsThe Th227 decays to Ra223 in a decay process with a half-life of 18.2 daysThe Ra223 decays to Rn219 in a decay process with a half-life of 11.4 daysThe Rn219 decays to Po215 in a decay process with a half-life of 4.00 secondsThe Po215 decays to Pb211 in a decay process with a half-life of 1.78 millisecondsThe Pb211 decays to Bi211 in a decay process with a half-life of 36.1 minutesThe Bi211 decays to 99.7% Tl207 and 0.3% Po211 in a decay process with a half-life of 2.15 minutesThe Tl207 decays to Pb207 in a decay process with a half-life of 4.79 minutesThe Pb207 is stable and hangs around for the balance of eternity

The first thing to realize is that an instant after the imaginary start with pure Uranium235, and continuing for many billions of years, we have a constantly changing mix of various isotopes of elements, shading from pure U235, and asymptotically approaching (but never mathematically quite reaching) pure Lead207.

The constituents of that mix are busy decaying all at their own rates.

But the individual decay rates are mathematical models. A tiny little bit of that U235 has already changed all the way to Pb207 within the first hour, and a tiny little bit is still stuck at U235 after some billions of years. The rate of each individual decay process averages out to the half-life given by the particular model for that process.

So to get all the way to the point: yes, you actually can effectively change the rate of transmutation of the stuff that comes out of the reactor. You can re-enrich it back to a sufficiently rich mixture of uranium and plutonium oxides (and do some other reprocessing chores, such as cleaning out the fission poisons so it's usable again) and put it back in a reactor. Or you can separate out the plutonium and put it in a nuclear bomb and that will transmute really fast if you set it off. After you take out the plutonium it is at least theoretiucally possible to re-enrich the remainder back to 5% U235 and put THAT back in a reactor.

Note that the process during reactor operation is not the same as the decay process. In the reactor, you can "use up" a substantial percentage of the starting U235 in just a few years, in the process "creating" a bunch of plutonium (more than one isotope!) where there was none.

but we have no ways to actually dispose of it other than to wait for millions of years.

If it has a half-life long enough that it will be around for "millions of years", then it's pretty much harmless.

Note that Pu-239 has a half-life of 24100 years (making it not very radioactive at the best of times), and in a million years 99.99999999997% of it will be gone (in other words, 100,000 tons of it (more than is to be had in the world today by a large margin) will be reduced to 32 micrograms).

"We keep creating all this waste that we have no way to actually dispose of."1) Most of the waste isn't really radioactive.2) The waste the is radioactive can be reused3) We have perfectly good ways of storing it, but politics gets in the way.

The great pacific garbage patch is largely a myth.

A pit I mile to a side can hold all out garbage for the next 500 years. Our trash problems largely comes form putting dump that are two small just a few miles from the edge of an expanding city, and the fact that it is

We can treat it, put it in a concrete cask, and store the casks somewhere, but we have no ways to actually dispose of it other than to wait for millions of years.

Not really true its more a political problem than anything. The casks are in some senses better than burring the stuff because we can get to them. If we could get over the political hurtles around breeder reactors not only would we stop producing almost all the spent fuel waste we could actually start using the existing spent fuel in the casks as new fuel. That would leave us with a very tiny amount of spent fuel in terms of sq feet of storage required. It would also leave us retired reactors and plant

Medical/industrial toxic waste is still dangerous and can be used for making dirty bombs designed to spread said nuclear waste over a large area. Not incredibly deadly, but very expensive to clean up, it must be carefully and properly disposed of. I remember reading about a dental x-ray machine that was improperly disposed of and was basically taken south of the border and dumped. Somehow the container of nuclear material burst or was broken open and little kids played with the powder inside. I never he

Yet another contractor who seems to have been doing the minimum required to get paid. Fire suppression turned off, flammable materials stored after repeated inspections required that they be removed. Outsource responsibility and this seems to be the result.

At what point do we stop blaming the contractors and start blaming a lax regulatory environment (which the contractors probably lobbied for)?

I expect the free market to behave like a 5 year old on a sugar rush.What I can't accept is the adults' repeated refusal to punish bad behavior.We have a regulatory framework. Enforce it.

Yet another contractor who seems to have been doing the minimum required to get paid. Fire suppression turned off, flammable materials stored after repeated inspections required that they be removed. Outsource responsibility and this seems to be the result.

What I can't accept is the adults' repeated refusal to punish bad behavior.
We have a regulatory framework. Enforce it.

I'm sure everyone in the chain of command, who isn't a political appointee, would agree with you.
The problem is, "corporations are people, too", and they've paid to elect people who agree with them; that there's just nothing they could have done in this case, and it was, sadly, just an unavoidable accident.

True enough. If only nuclear waste facilities were held to the same regulatory standards as, say, fertiliser plants in Texas [slashdot.org] which are totally innocuous since they don't store any nuclear waste on their premises.

*Impossible because the rules in the US are as such that you are not allowed to do anything that could result in threatening the revenue stream to current nuclear energy giants. Guess who helped write them?

Technological solutions exists but China will have a solution within 10-20years and we will buy from them because of these "Super Important" laws.

When that happens, the US will rightfully become the banana republic it so desperately want to become.

Nuclear waste from once through (no reprocessing) is 99,3% fissionable material for light water reactors, about 98,7% from heavy water reactors.There are reactors designed to take this fuel in and fission it completely, Molten Salt reactors and Sodium cooled fast reactors.There is no commercially operational molten salt reactors and sodium cooled reactors in commercial operation only in Russia sphere of influence.But there is a solution. The real problem is after Three Mile Island nuclear is seen as an evil

I believe we need an all of the above solution (nuclear, solar, wind, biomass,...). In reality, nuclear is just lip service, it's not really an all of the above solution. So I'm very loud when I sense the lip servicing, in the direction of exposing the lie (the lip service BS).

Nuclear is the only solution that could provide electricity to 100% of the world needs. The ONLY solution. Solar and Wind require huge technological breakthroughs in energy storage that are still in the future.

I believe we need an all of the above solution (nuclear, solar, wind, biomass,...). In reality, nuclear is just lip service, it's not really an all of the above solution. So I'm very loud when I sense the lip servicing, in the direction of exposing the lie (the lip service BS).

Nuclear is the only solution that could provide electricity to 100% of the world needs. The ONLY solution. Solar and Wind require huge technological breakthroughs in energy storage that are still in the future.

Ooohrah. I'd mod you up if I had points. In exams which have an "all of the above" option, "all of the above" is nearly always the wrong answer. Though I must disagree with you on TMI being the point where nuclear was seen as evil. It was some time before then that the greenies turned against it. You might want to check out Rod Adams' blog "Atomic insights". http://atomicinsights.com/smoking-gun-robert-anderson/ may be of particular interest.

In the greenies world, nuclear was always an unacceptable evil. But if you look around, they protest even large hydro dams as well, claiming they are too expensive. They tried to abort construction of two large hydro dams in Brazil because "wind and solar would be less expensive".

The problem isn't the radical green mindset, it's when their opinion got traction and started infesting the general liberal mindset. That I believe happened as the main ripple effect of TMI.

"Impossible because the rules in the US are as such that you are not allowed to do anything that could result in threatening the revenue stream to current nuclear energy giants"that makes no sense since it's those same companies that would profit from reuse of nuclear waste.

It's New Mexico. You don't need a bedded salt formation. Just throw that shit anywhere, the whole state is a scrap heap (based on driving around the strech of wasteland between El Paso, White Sands Missile Range, and Carlsbad Cavern).

On a more serious note, why are we burying highly radioactive material instead of using it to generate electricity? If it's too hot to throw away, surely it's hot enough to spin turbines.

That's my point. It's a state composed almost entirely of barren desert wastelands, with occasional nuclear test sites sprinkled about. Dropping this transuranic waste there probably wouldn't have any measurable impact on the current background radiation levels.

Also, I'm joking. Lighten up and throw this stuff into a breeder reactor. One man's transuranic waste is another man's reactor fuel.

First off, you obviously know nothing about New Mexico. It is a beautiful state with a lot of interesting ppl (esp. the tribes). had I not responded here, I would have modded you down for this post
However, I fully agree with the rest. The idea of throwing away 'nuke waste' that is dangerous for 20K years, is insane, when it can be burned up and electricity is generated cheaply.

Honestly, I didn't really mind the landscape. A fascinating change of scenery compared to the eastern seaboard. I was mostly joking.

That being said, on route 54, somewhere roughly halfway between Alamogordo and El Paso, there's a little "Red Wagon Grill" food truck in a "town" called Orogrande. This guy makes awesome burgers. Worth the drive, especially if you have a radar detector.

Until its mandated that all nuclear operators must reprocess nuclear fuel at least twice this will continue, because it's cheaper to build nuclear fuel from freshly enriched uranium instead of doing reprocessing. Some will say "but reprocessing isn't legal". It is legal in the USA, it's just not done as it's more expensive than building fresh fuel.

This isn't politics, it's economics. Reprocessing of nuclear fuel was forbidden for a while late 70s/early 80s, but that prohibbition has been rescinded for decades.Now it's very likely that should a nuclear reprocessing facility starts, it will attract thousands of crackpot anti nuclear protesters from all over the world to protest that reprocessing is _____ (insert your favorite bad word).

Exactly. Nuclear power is already expensive, so what do you think will happen if the operators are forced to invest in reprocessing as well? They will close down their plants instead because they can't make a profit, or just demand further government subsidy.

Now it's very likely that should a nuclear reprocessing facility starts, it will attract thousands of crackpot anti nuclear protesters from all over the world to protest that reprocessing is _____ (insert your favorite bad word).

Even if that were true, you said it yourself: it isn't a political problem, it's an economic one.

But....... The main reason nuclear is expensive today is the result of a chicken egg problem caused since Three Mile Island:Nuclear became expensive after nuclear operators backed off from installing new reactors after TMI, nuclear has no chance of becoming cheaper because it has low volume of nuclear reactor installations.Nuclear could be at least 20% cheaper if there were scale/volume in the nuclear construction business and the NRC streamlined the regulatory process with a focus of providing a predictabl

Dam right. It doesn't just influence. In my opinion the nuclear power politics is essentially violently choking the nuclear industry (as far as new installations go).The real problem is with all the huge hoopla, revenue guarantees, political support and overall coolness around wind and solar, plus the explicit decision to invest essentially zero on R&D for new nuclear technologies (outside of minor improvements to water cooled, uranium fueled, fission plants), the game is rigged towards killing fission

But, as you say, there wasn't enough financial incentive to restart reprocessing in the US, so we've just stuck with new fuel ever since.

Gerald Ford "killed reprocessing" with a Presidential directive to shut down reprocessing in October 1976. But there was no plant to shut down at that point. (It is true that Carter also issued an Executive Order, but shutting down something that was already shut down, and forbidding something already forbidden means no change in the status quo).

The U.S. only ever had one reprocessing plant (as opposed to a weapons plutonium extraction plant) which was at West Valley, New York [ny.gov] which was shut down in 1972 d

Also known, in every country with a halfway-sensible nuclear policy, as "reactor fuel."

... if by "reactor" you mean "radioisotope thermal generator". That's actually an intriguing variant on the silly "shoot it all into the Sun" idea. Build spacecraft to explore the out solar system, placing the material far away from mischief, and call the cost of the spacecraft a "disposal fee".

Unfortunately the real issue in this story isn't the inherent danger of the materials, but the doubts the story raises about whether we as a nation are responsible enough to handle such materials.

That's the wrong way of looking at things. Reprocessing is about recovering usable fuel material, it's not about reducing waste and it actually results in increased amounts of nuclear waste. Lots of neutrons flying about do that sort of thing to equipment used for reprocessing. It's also difficult due to the high strengths and melting points of the materials in the fuel rods. It's potentially useful, and there's a new US facility doing it or about to do it, but it's not waste disposal method.There's als

Ummm, no. That's a bit like saying the contents of a kebab shop's grease trap is organic so it will work perfectly well as fuel in your car engine, just pour it in and turn the key and away you go. The nuclear equivalent of the AAA is just a phonecall away after all.

Some transuranics aren't fertile, they produce less than one neutron per fission event on average so they damp out the chain reaction needed to keep a reactor operating. Some have a low cross-section, they're difficult to hit with a moderated ne

The problem is that any waste-burning reactors will still have to pay their way by generating electricity at an affordable price even with an offset for the value of destroying some waste. The BN-series reactors the Russians are building and operating and the Chinese are considering buying can burn waste but not a lot of it and they require highly-enriched uranium and plutonium to generate the neutron flux needed. The financial details of how much the existing BN-series reactors cost to run are not transpar

"The problem is that any waste-burning reactors will still have to pay their way by generating electricity at an affordable price even with an offset for the value of destroying some waste."

I disagree. If they never make a dime we still need them; we have too much of this high level waste, and apparently nowhere to bury it. And I'm not sure that's such a bad thing. Not if it's going to be hot for 10,000 years. We have no choice now, but to burn this stuff up.

There are plenty of places to bury waste, even spent fuel if the owners don't want to reprocess it. The fact is there isn't really a lot of spent fuel or reprocessed fuel waste around at the moment to dispose of. France, which has run forty power reactors for thirty years and more has a few hundred cubic metres of vitrified high-level waste and that's all. It's not a Hollywood movie scenario where this waste will start roaming the countryside destroying everything in its path with its fiery breath or conver

The US nuclear lobby killed the experimental reactor that was designed to do that sort of thing and drove it's project leader out of the industry because he dared to say something could be safer than current reactors.Next question?

Can someone explain to me why a reactor can overheat and meltdown like in Japan... but not have the energy to spin the turbines to power cooling?

How can it get so hot that it boils the water way even under ridiculous pressures... but that heat can't be used to power turbines?

Am I to believe that reactors actually generate more power when shutdown than when powered up?

I just can't fathom why a plant can SCRAM and then overheat... but be unable to cool itself. Someones design is WAY fucked up me thinks. Its generating too much steam... USE IT...

It can. The main problem with this type of operation is that the main generator and turbine are not designed for very low power operation, there is not enough steam pressure to drive them below a minimum threshold (~5-10% power). The Chernobyl accident occurred during an attempted test to see for how long the reactor could run its cooling pumps on decay heat after shutdown (the accident was not caused by this test directly, but due to the inappropriate actions by the operators leading up to the test).

You can't design a system to use an infinite amount of steam, and the Fukushima distaster, you couldn't contain the steam because of damage to the facilities (which, of course, got much worse after the meltdown). The design of the reactor was old, and has been superceded by more fail-safe designs, but that is not the root cause of the disaster. The root cause is the failings fo Tepco install and manage the reactors in a safe manner (high enough from the sea, not have its backup generators in the basement, l

Because the high temperature of the molten fuel, you can't design a container for it, and without a container, you can't pressurize the steam to spin a turbine.

Your other question, about why a plant can SCRAM and still overheat; yes, someone's design IS way fucked up. These older-design reactors create a large amount of short-lived decay products, (basically, the leftover bits of atoms after the uranium nuclei split) - some of these are stable, and most are not, and they will also decay. When these decay p

The real problem is that these are antiquated system and they did NOT have diesel back-ups like they were required.
Instead, they need NEW reactors that have designs that will prevent anything like this from happening.
That is the advantage of the thorium design. ZERO chance of a meltdown unless laws of physic are broken, or the reactor is actually sabotaged from internally.

They actually had emergency cooling available at the time. There were some news reports that the lack of cooling was due to a lack of power, but that wasn't actually the case. They had backup batteries to run the pumps, and when that didn't seem to be working they had fire engines to pump water into the system. It's true that they should have had more available, but what they did have would have been adequate if it were not for the damage done by the earthquake. Not the tsunami, that did damage too, but he

You have and earthquake so the rods get pushed in to stop the reaction - fast - you don't want the warped equipment of a reactor after an earthquake with the a number of rods stuck.
You then have to cool over a long time - lots of big expensive pumps running from big diesel generators vs all the heat.
If your cost cutting you dig your plant low into strong ground to pass regulations on known earthquake events - near an ocean going that low is not so smart.
After water starts flooding your big diesel generat

Seriously, we need small reactors that use thorium like we had a couple of decades ago. We can get this going again in less than 5 years. With these, we can either augment current sites, or even replace current reactors and then burn up the waste, while getting energy.

Considering that the west is dealing with issues from Russia because of reliance on Russian energy, AND we have AGW occuring AND we have 'waste' disposal issues, I would think that the west would be smart enough to burn up all of that energy, and then bury only 5% of what they were going to. Heck, WIPP would handle EVERYTHING that we had left, and everything would be safe within 200 years.

Why not just finish the integral fast reactor programme and use the spent fuel? Iirc, the project was almost finished when it was abruptly terminated back in the early 90's due to political interference.

That would result in reuse of some high grade nuclear waste but doesn't make it all go away by magic. You'd need both the new reactor and a better solution to high grade waste other than shoving it in drums and putting it somewhere the taxpayers won't notice. There are long term storage solutions but little desire to commit the resources to use them.

Encapsulation of high grade nuclear waste (sealing it in glass) has been done for decades, and a much better chemically stable approach, incorporation, has been worked on for decades and is now in use (Synroc).Shoving things in drums and hoping they stay dry is a shortcut that is going to fail eventually.

1) Chose a subduction zone,2) bury $Stuff_we_don't_want right next to it, a few km below the local ground surface.3) wait for mother nature to push it down and dilute it in billions of tons of molten rock.4) profit? nah, it's expensive... but at least don't worry about it.

1) mantle convection [wikipedia.org] simplified2) The word "dilute" in step 3. If you have a thousand tons of U235 surrounded by 5km of rock and melt it all, how much U235 can find an updraft toward a volcano, since you were dumb enough to drill next to an active volcano?

How dare you propose a solution which is both workable by examples in France and Japan, and fails to support the idea that wind and solar can provide all the power we need (ignore the Solyndra behind the curtain)?!?!?!

I'm pretty sure we burned Joan of Arc at the stake for less than that!

The reprocessing canard has gone on long after plenty of information about it's future pitfalls has been in public record. See Here: http://spectrum.ieee.org/energ... [ieee.org]
"MOX is also three times as hot as spent uranium fuel, thanks to an accumulation of transuranic isotopes such as americium and curium, making it less fit for underground storage.
Therefore, according to a 2000 consensus report on reprocessing prepared for France’s prime minister, spent MOX must cool for 150 years( in a water pool) befor

Thank you, I've always wondered why these types of waste were not reprocessable. A friend of mine went to ASU in the '70s/'80s and they had an Indian physicist called Dr. Roy (no idea what the last name was) who claimed to have a method for safely disposing of nuclear waste, never heard of the program going live.

Cost to get to the sun isn't too bad; you don't need the fuel to create a stable orbit, and you're "falling" into the biggest gravity well around. Still, you have a point about the cost of launching something with so much mass.

Hint: Earth orbit is ~100km/s. Solar escape velocity when starting at Earth is ~50km/s. So it is twice as expensive to hit the Sun rather than Alpha Centauri.

LOLOLOL! No, really man. You DO need to check your math. Or just, do your math instead of guessing.

See where you say Earth's orbit is 100km/s? No. It is ~30 km/s. You probably got confused by somebody writing 100k km/h and remembered it is per second, or forgot to convert units. You got the ~50km/s because you remembered the ratio of energy from the classwork and made a crude guess that would be wrong in either case. The needed escape velocity is only 42km/s.

You found a link, but you did not take the time to THINK about the IDEAS that I expressed. That link does NOT address what I said; it does the math for LANDING on/in the Sun, not for driving to the nearest slingshot and using that to alter course and crash into the Sun. So you replied without having even attempted to understand what I said. Tsk tsk.

Because are wrong. I am not talking about landing on the Sun. You need to get rid of the "horizontal" delta-V of the Earth. "Vertical" delta-V is a non-issue; the Sun's gravity can provide plenty of that, but that only helps you once you get rid of your horizontal delta-V. Otherwise you keep missing.

And yes you only need to get rid of enough horizontal delta-V to strike the outer parts of the Sun. The difference is negligible.

Keeping in mind you're claiming to have been mentioning it, I suggest you go back and re-read your posts, and stop replying to me. I don't need an apology, but you clearly missed the point, argued against something different than what I said, and are now claiming you didn't. LOL

Or, now that you're on the right subject, it should be OBVIOUS to you that the minimum amount of fuel required is the SAME. Not double. And the thought experiments for DIVING into the Sun, aka Landing on it, is totally not relevant.

You also remembered your coursework, good job! Now go back, re-read the problem, re-read his link, understand the formula used. It is the formula for LANDING on the Sun. Not for crashing into it. And using a gravity well, even landing on the Sun only requires fuel to get to the nearest object you can use to slingshot (the Earth, presumably on the next orbit). It is the SAME fuel cost for both; less than the link describes. Not only can you crash into the Sun on less fuel than they describe, you can also lea

Deserts are usually less exploitable by humans, but they are extremely valuable to the planet. Through sorry experience we have learned that desert ecosystems are easily damaged. Vehicles driving across the surface can crack and break the crust of micro-organisms ("desert pavement") where the damage can last for centuries.

The thought process of "Humans cannot immediately exploit the resources, therefore it is worthless" is extremely foolish.

Just look at what humans have done to resources we consider valuable. Deforestation of entire contents, fishing out oceans to possibly the point of exhaustion. Desert regions are one of the few resources left mostly intact from human destruction.

Depends on what you consider damage. I submit that the tank and vehicle tracks left in desert areas during WW II exercises 70 bloody years ago might still be visible.. but I hardly consider them damage. You'll have to prove the value of "desert pavement" to me first. And your claim that deserts are "extremely valuable to the planet" is questionable too. I submit that the Gobi Desert was a lot more useful to the dinosaurs fossilized there when it was green and lovely than it's been for the past dozens o